An agricultural harvester known as a “combine” is historically termed such because it combines multiple harvesting functions with a single harvesting unit, such as picking, threshing, separating and cleaning. A combine includes a header which removes the crop from a field, and a feeder housing which transports the crop matter into a threshing rotor. The threshing rotor rotates within a perforated housing, which may be in the form of adjustable concaves, and performs a threshing operation on the crop to remove the grain. Once the grain is threshed it falls through perforations in the concaves and is transported to a grain pan. From the grain pan the grain is cleaned using a cleaning system, and is then transported to a grain tank onboard the combine. The cleaning system includes a cleaning fan which blows air through oscillating sieves to discharge chaff and other debris toward the rear of the combine. Non-grain crop material such as straw from the threshing section proceeds through a straw chopper and out the rear of the combine. When the grain tank becomes full, the combine is positioned adjacent a vehicle into which the grain is to be unloaded, and an unloading system, e.g., an unloading auger, on the combine is actuated to transfer the grain into the vehicle.
A typical header includes one or more cutters, e.g., cutter bars with reciprocating knives, which cut the crop material that is harvested from the field. Once the crop material is cut, a conveyor system, which is positioned rearwardly of the cutter(s), transports the crop material to the feeder housing. Modern headers generally have cutters and attachments which are specifically optimized to harvest a particular kind of crop material. For instance, the header may include a rotating reel with tines or the like to sweep the crop material towards the cutter(s). Alternatively, the header may include snouts and row units instead of a rotating reel and cutter bar(s).
A draper header is typically used to harvest fluffy or bushy crop material such as soy beans or canola. A draper header generally includes a conveyor that is in the form of one or more flat belts, known as draper belts, to convey the crop material to the feeder housing. Typically, a draper header may include two lateral draper belts that convey the crop material longitudinally inward and a center feed belt that conveys the crop material into the feeder housing. Each draper belt may be wrapped around rollers, for example various combinations of drive rollers and idler rollers. The draper belts may include cleats extending transversely across the full width of the header, which contact the crop material to help facilitate its transportation into the feeder housing.
Some draper headers are moveably mounted such that the elevation, roll, and/or pitch of the header may be adjusted, allowing the header to more aggressively harvest crop material. Lateral tilt cylinders may be incorporated to roll the header laterally (e.g., tilting left up/right down). An additional hydraulic cylinder may be added to control the pitch of the header (tilting fore/aft). Also, the position of the rotating reel and/or the angle of the cutter bar(s) may be adjusted. Specifically in regards to a flexible cutter bar, the flexible cutter bar may be equipped with actuators that adjust the vertical height of certain sections of the flexible cutter bar with respect to the frame of the header. For example, in the case of an undulating field, a header may continually alter the angle of its cutter bar(s) and/or the vertical height of its cutter bar(s) at various points along the cutter bar(s) in order to match the undulating terrain and harvest crop material which otherwise would have been left on the field.
Flexible draper headers having a flexible cutter bar can be tremendously instrumental in reducing header loss. However, although the greater flexibility of the cutter bar increases the crop material that is cut, it may cause header loss or damage the draper header. A flexible draper header may lose cut crop material at the stage of conveying the cut crop material onto the draper belts. For example, crop material may be lost between the distance from the point the crop material is cut to the front edge of the flexible draper belt. As the cutter bar tilts more forwardly and/or flexes vertically up or down, this distance or gap, may become greater as the cutter bar moves further away from the front edge of the flexible draper belt. Thereby, cut crop material and/or debris may be wedged or fall through this gap between the cutter bar and draper belt as the cut crop material is transferred onto the draper belt. Further, lodged crop material and/or debris may cause increased friction or wear on the draper belt, which may shorten the operating life of the draper header.
Various seal arrangements are known for reducing or preventing the infiltration of cut crop material and/or debris in between the distance from the cutter bar and draper belt. One such arrangement uses a flexible draper belt that completely flexes in accordance with the cutter bar, for example as disclosed in U.S. Pat. No. 7,478,521. However, with greater flexibility comes inflated manufacturing cost and increased maintenance to sustain the additional moving parts of the flexible draper header. Alternatively, a partially flexible cutter bar may be incorporated such that the cutter bar is relatively inflexible and thus the distance between the cutter bar and the draper belt is minimized. These arrangements may still cause header loss as some crop material may never be cut by the more rigid cutter bar. Other arrangements use an intermediate flex floor to span the distance between the stationary draper belt frame and the flexible cutter bar, for example as disclosed in U.S. Pat. No. 7,975,462 and owned by CNH Industrial. Known flexible draper headers may either improperly restrict the movement of the flexible cutter bar, may be costly to manufacture, and/or may be arduous to maintain and therefore are impractical for long-term operation.
What is needed in the art is a draper header which has a flexible cutter bar and a flexible draper belt that is cost effective and not burdensome to maintain.